Vehicle body closure panels, such as a tailgate, are pivotally mounted between body side panels forming the pillars at the rear of the vehicle. The tailgate pivots about a hinge axis between a horizontal, open position and a vertical, closed position. Preferably, the mounting assemblies for the tailgate permit the tailgate to be removed, and this has been accomplished in a known construction when the tailgate is pivoted to a position between the fully open or fully closed position. For example, the tailgate may include hinge pins that extend outwardly along the hinge axis that removably connect into brackets carried on the truck body. When the tailgate is pivoted to a predetermined intermediate position, for example, 15° away from a fully closed position, at least one of the hinge pins slips through a slot in the connecting bracket as the tailgate is lifted at one end from the truck body.
Some of the tailgate mounting assemblies include a spring bias assist for assisting movement and counterbalancing the weight of a tailgate during opening or closing movements. One previously known mechanism in which a torque rod provides spring biasing between the tailgate and the body panel pillars carries the torque rod on assemblies that form the pivots for the tailgate. Since the torque rod forms a portion of the pivot assembly, the torque rod must be installed for the tailgate to pivot and thus complicates the assembly procedure. Moreover, the torque rod may require particularly configured ends that complicate production of the parts before assembly.
A previously known tailgate assembly may use hinge pin trunnions for pivoting and the torque rod is pre-formed and installed into the tailgate in a complex and intricate procedure. For example, during assembly of the tailgate, the stationary end of the rod has to be aligned with an aperture that exposes the end for attachment outside of the tailgate while the anchoring end is aligned with a reinforcement plate located inside the tailgate. All of the aligning must be performed while the torque rod is carried within the interior of the tailgate and the procedure may be difficult and time consuming. Moreover, numerous components are required to assemble the torque rod to the tailgate. Other types of springs used in place of the torque rod are difficult to install within the confines of tailgates made of inner and outer panels joined together before the hinge assembly is mounted. Moreover, such assemblies may be difficult to repair, and replacement parts are complex and expensive.